The Ford New Holland FD81812566 pinion is a genuine OEM replacement part designed for a wide range of Ford agricultural and industrial machinery. This essential component ensures proper power transmission within the specified models. It replaces part numbers C5NF11350C and 81812566, providing reliable performance and compatibility for Ford 2000, 3000, 4000, 5000, 7000 series tractors, along with 2600, 3600, 4600, 5600, 6600, 7600, and various industrial models including 231, 233, 333, 335, 420, 531, 532, 535, 2100, 3100, 4100, 2110, 3110, 4110, 4140, 3400, 3500, 3550, 4400, 4500, 5500, 5550.